This grant application seeks continued support for the Pediatric Oncology Group (POG) activities of the Southwestern Medical School Consortium, which consists of the University of Texas Southwestern Medical School (Dallas) and Cook-Fort Worth Children's Medical Center (Fort Worth). Since joining POG in 1981, this partnership of children's cancer treatment and research centers in North Texas has grown to become the Group's largest contributing member with regard to patients enrolled annually on therapeutic studies (over 100 per year). Moreover, during the current grant cycle, investigators from Southwestern have risen to positions of leadership on major Group committees, including the Executive Committee, New Agents and Pharmacology Committee, and Lymphoid Relapse Committee. Southwestern investigators have also served and are serving as study coordinators of over 20 POG treatment protocols, including studies of acute lymphoid leukemia (ALL) in first marrow relapse, advanced stage undifferentiated lymphoma, B-cell ALL, advanced stage large cell lymphoma, neuroblastoma, bone marrow transplantation, and a number of Phase II studies. Moreover, investigators in the Consortium have has prominent roles within the Group in the areas of data management, protocol development, pharmacologic monitoring, and supportive care. Results of pilot studies conducted at Southwestern, in particular the Dallas/Fort Worth (DFW) protocol for non-T, non-B ALL, have been shared with the Group, and the data have been used in the construct of the next generation of POG protocols. We now affirm a continued commitment to POG research during the next 5 years. This grant proposal describes the personnel and facilities in the Consortium centers (including for the first time Scott & White Clinic), involved in numerous cancer research arenas, within and outside POG. Specifically, during 1991-1995 we aim to advance POG research by: 1) actively enrolling as many patients as possible on POG treatment, laboratory classification, and epidemiologic protocols; 2) collecting, recording, and submitting all necessary research data accurately and in a timely fashion on order that our protocol entries continue to receive a high rate of evaluability; 3) making scientific contributions to the Group through active participation on key committees, as disease committee chairmen, and providing service as protocol coordinators and consultants to the Group's leaders; and 4) continuing to conduct innovative in-house pilot studies to be used later by the Group.